Crush ribs are a great way to stop tweaking files per-printer and still get that snug fit you need for good mechanisms. Here’s a short video explaining the why, the where from, the how, and more.
Also, here’s a follow up tip about how to make crush ribs draft quick fast.
Did that help you? Did you use it in a design? Let me know so I can share it with everybody.
I thought that the hard part would be making the Six robot arm. Turns out making a two finger gripper is also pretty challenging! I would love to see students take on this challenge to make their own gripper. There’s so many ways to tackle the challenge.
The gripper must:
More to follow as this adventure unfolds! Wish us luck.
Discuss this post in the forums.
So you’ve played with the Makelangelo‘s generated Gcode and now you want to experiment on your own. Cool! Here’s a simple rectangle to get you started.
Now let’s give some values to these parameters:
| A | 20 |
| B | 40 |
| C | 10 |
| D | 30 |
My method is to lift the pen, drive to a corner, put the pen down, and then trace the rectangle. That means going to five points because we have to come back to the start.
G0 Z90; # pen up G0 X-10 Y20; # p1 G0 Z40; # pen down G0 X30 Y20; # p2 G0 X30 Y-40; # p3 G0 X-10 Y-40; # p4 G0 X-10 Y20; # p1 again G0 Z90; # pen up
And voila! I’ve deliberately done this with the origin away from the center so the numbers are more obvious. I hope you see that in a cartesian system the origin could be anywhere. For example, if it were below and to the left of P4 all the X and Y values would be positive.
The Sixi Calibration Tool helps anyone using a Sixi robot make sure that the robot’s mental and physical states match.
If they do not match then the move you expect is not the move you will get. This could very quickly lead to an accident.
There has to be a way to synchronize the mental model and the physical model. The calibration tool is made to fit in one place and attach to the arm in only one way. This forces all the robot joints to move to known angles. Those angles are measured in the mental model in Robot Overlord and then copied to the physical model in the robot’s brain.
| Joint | Angle (degrees) |
| 0 (x) | 0.0 |
| 1 (y) | -41.3 |
| 2 (z) | 74.5 |
| 3 (u) | 0.0 |
| 4 (v) | -33.5 |
| 5 (w) | 0.0 |
Sixi robot now has a URDF description and can be found on the ROS wiki.
ROS (Robot Operating System) was first developed by Willow Garage, a Boston robotics company. Though Willow Garage no longer exists, the ROS has been so successful that it has outlived its creator.
Since ROS is such a popular tool, I hired sachinkumar1235 on Fiverr who built the URDF package. It includes decimated STL files created by Andre.
You can now find Sixi robot on the ROS wiki, or grab the package directly from the Sixi robot github project.
